In the production of "textile" or continuous glass filaments there has been a never ending quest to increase the throughput and operating efficiency of the filament forming systems. To increase the throughput, some feeders have been designed with a greater number of orifices, while other systems have attempted to increase throughput by raising the operating temperature of the feeder and of the glass. In either case, the cooling systems must remove more heat. One of the most widely employed cooling systems consists of a plurality of blade-like members or fins that are attached to a water cooled header for removing heat from the forming zone and glass.
In the "operating" or "running" condition, the continuous filaments are mechanically drawn away from the feeder at high speed which drags or pumps the surrounding air along with the filaments which, in turn, induces air to flow into the interior of the forming zone which provides some cooling of the molten glass.
A condition known as "hanging" occurs when at least some, and usually all, of the filaments are not being drawn at production speed and molten glass continues to flow lazily from the feeder. While hanging, the induced air flow into the fiber forming zone due to the high speed advancement of the filaments is obviously not present if no filaments are being drawn. The lack of induced air flow, decreases cooling.
The forming system must be adequately cooled during "hanging" to permit the filament attenuation to be quickly restarted after disruptions in filament attenuation that frequently occur. Without adequate cooling, rapid re-start of filament production becomes exceedingly difficult, reducing the operating efficiency of the system. Historically, the cooling requirements of the filament forming system in the "hanging" condition have been a significant factor in limiting the throughput and operating temperatures of forming systems.
The present invention dramatically increases the heat removal from the forming zone during the hanging condition, as well as significantly increasing the heat removal from the forming zone during the running condition. Accordingly, utilization of the concepts of this invention will provide increased throughput and operating efficiency for a continuous filament forming system.